package priv.pront.code.mati.province.comp;

import java.util.Scanner;

/**
 * @Description:
 * @Author: pront
 * @Time:2023-11-18 14:07
 */
public class Main2 {

    static String s;
    static int[] a;
    static char ans = '0';
    static int max = 0;
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        s = scanner.next();
        a = new int[26];
        for (int i = 0; i < s.length(); i++) {
           char cur = s.charAt(i);
           a[cur - 'A']++;
        }

        for (int i = 0; i < a.length; i++) {
            if(a[i] > max){
                max = a[i];
                ans = (char) ('A' + i);
            }
        }
        System.out.println(ans);

    }
}
